1. Field of the Invention
The present invention generally relates to a sprinkler for irrigation of a square or other polygonal land area which includes a nozzle discharging water in a lateral direction as the nozzle rotates about a substantially vertical axis. A water powered drive mechanism including a unique gear arrangement causes variation in the speed of rotation of the nozzle with the nozzle moving at a relatively slow rate of speed when irrigating corner areas of the land area and at a higher rate of speed when irrigating the intermediate straight-sided portions of the land area. The nozzle includes a diffuser structure to reduce the length of trajectory of the water when irrigating the straight-sided portions of the land area with the diffuser being actuated by the drive mechanism.
2. Description of Relevant Art
Sprinklers for irrigating large land areas have been utilized for many years with various arrangements being provided to distribute water in a desired pattern. Sprinkling devices are generally categorized as stationary permanently set sprinklers or movable sprinklers. Stationary sprinklers include structure which utilize underground or above ground supply pipes having one or more discharge nozzles connected therewith. Movable sprinklers include travelling sprinklers either of the linear or center pivot type driven by water power, electrical power, and the like. One of the problems which has existed is the discharge of an equal quantity of water onto all increments of the land area being irrigated. For example, irrigation sprinklers utilizing rotatable nozzles or elongated pipes and nozzles rotating about a center pivot will accurately irrigate a circular area but inadequately irrigate the corner portions of a square or polygonal area. Many efforts have been made to vary the circular pattern of a rotating nozzle such as by changing the angle of discharge from the nozzle, varying the pressure and thus volume being discharged at particular areas by various means such as cams, electrical devices and the like. While such devices have worked effectively in some instances, they are usually complicated thus requiring considerable maintenance and subject to failure and quite expensive to install and operate.